0.4.0

Mostly a technical release, I move the whole application to micronaut !

Also :

• add configuration options to size and sort order [#28]
• update README.md with all the configuration available.
• improve development environnement thanks to micronaut (works both in docker or with gradle)
• fix some sse bug on search topic data
• update to last gradle version

⚠️ The configuration file have changed in order to match Micronaut requirement ⚠️